Certain benzimidazole derivatives



United States Patent 3,247,217 CERTAIN BENZIMIDAZOLE DERIVATIVES Ferdinand Grewe, Cologne-Stammheizn, Helrnuth Kas- 12 Claims. (61.260-299) The present invention relates to and has as its objects new and useful organic compounds, the production thereof and their use as protective agents" against fungidiseases on plants. 'The new compounds according-to the 'present'inven-tion may be represented by the following general formula:

wherein one of the radicals R R and R stands for a lower alkyl radical with 1 to about 4 carbon atoms which may also be substituted by hydroXyl groups, another one for a higher alkyl radical with at least 8 carbon atoms and the remaining radical for an aryl residue, R stands for a substituent of the benzene nucleus, X denotes an acid radical, which renders the molecule water-insoluble or diflicultly soluble in Water.

It is known that water-soluble salts of 1-methyl-2- phenyl-3-dodecylbenzimidazole can be used as disinfecting agents with fungicidal or bactericidal action (see, e.g. German patent application 1,040,752).

Furthermore it is known from US. patent specification 2,782,204 that certain 1,3-di-higher-alkyl-benzimidazoline-bromides possess fungicidal properties which makes them useful in the field of disinfection. It is also known from J. Pharm. Soc. Japan, vol. 63 (1943), pages 593- 599, that certain 1-higher-alkyl-3-lower-alkyl-benzimidazoline salts may be used as inert soaps and that some of the compounds mentioned in the aforementioned journal also possess bactericidal action useful in the field of dis infection,

All these compounds, however, were as yet notused for the protection of living plants, because they damage them or because their effect is only of short duration.

In accordance with the present invention it has now been found that water-insoluble or slightly soluble salts of the above mentioned compounds are highly active against fungi causing plant diseases.

The preparation of these salts can be carried out according to methods known as such. In its simplest way aqueous solutions of the soluble components are given together in about equimolecular proportions. But sometimes also aqueous .alcoholic solutions of the starting materials may be used.

The above mentioned water-insoluble or difficultly soluble salts are new agents for the protection of plant cultures. They are highly active against phytopathogenic fungi and readily tolerated by the plants.

As it can be seen from the formula, the position of the lower alkyl group and the aryl group in the compound may be interchanged. Thus, for example, the salts of 1-phenyl-2-methyl3-dodecylbenzimidazole are just as active as the corresponding salts of the reversed compound. As it is to be seen also substituents (R preferably lower alkyl, alkoxy radicals, nitro groups, chlorine 3,247,217 Patented Apr. 19, 1966 atoms, bromine atoms and the like, may be present in the benzene ring of the benzimidazole or also in the aryl radical standing in the 1- or 2-position.

More specifically the ions X which render the benzimidazole water-insoluble are complex-ions such as S03 naphthalene-1.S-disulfonate j (cli) iiitrop henyl-sulfoIrate pentachloro-phenate Z-mercapto-benzimidazolate Z-mercapto-benzothiazolate The salts of the aforesaid type are highly active against, for example, the following fungi which are the agents of economically important plant diseases, without thereby limiting the action of these fungi:

Phytophthora infesrans Alternaria solani Plasmopara viticola Venturia inuequalis Cladosporium fulvum Botrytis cingrea It "is of great practical importance that the compounds 0 according to the invention are also active against fungi By their application in practical plant protection it is therefore possible not only to combat downy mildew fungi but also to contain powdery mildew diseases occurring simultaneously in the same plant cultures to such an exe t that t ey o l r au e ny co omica ly importa damage. The majority of organic fungicides which are at present used for practical plant protection against downy mildew fungi are not effective against powdery mildew species and are even suspected of conditioning the plant cultures for the development of powdery mildew fungi, their practical value being thereby increasingly diminished. The preparation of the new compounds and the fungicidal properties of the compounds according to this invention are illustrated "by the following examples:

Example 1.Phythophthora infestans on tomatoes Young tomato plants (Bonny Best) are sprayed with aqueous emulsions in the stated concentration. 24 hours later, when the plants have dried off, they are placed in a moisture chamber at random and inoculated by sprin kling over with zoospores of Phy thophtlzora infestans. They remain, until evaluation on the sixth day after inoculation, in the moisture chamber at 18-20 C. and a rela tive humidity of 98100%. The casualty rate of the treated plants is given in percent of the casualty rate of the untreated controls whose casualty rate is taken as 100. Untreated plants are completely destroyed by the fungus.

The aqueous emulsions have been prepared by adding 1 gram of the finely powdered active ingredient to 50 ml. of acetone containing 6% of a non-ionic emulsifier (benzyl hydroxy polyglycol ether) and then diluting this mixture with water to the desired concentration indicated in the table below.

TAB LE 1.-PH YTH OPH TH ORA INFESTANS/TOMATOES Casualty rate at preparation concentrations in Preparation pereent 1-mcthy1-2'pheny1-3-dodecyl-benzimidazole-hexaeyanoierrate 4 17 25 1-methyl-2-phenyl-3-dodecyl ole-2-nitrobenzenesullonate 11 14 23 1-methy1-2-phenyl-3-dodocyhbenzimidazle-2A-din itrobenzene-sulfonate 16 26 28 1-phenyl-2n1etl1yl-3-dodeeyl'benzimidazole-O-nitrobenzene-sulionate 41 l-methyl-2-pheuyl-3dodeeyl-5-ethoxy-benzimidazole-rcin 17 22 l-methy1-2-p'methoxyphenyl-B-dodeeylbenzimidazole-hexacyano-l'errate 29 1-methy1-2-pheny1'3-dodeeyl-benzim a ole-O-nitro-benzene-sullonate 18 37 l-inethyl-2-phenyl-3-dodecyl-benzimidazole-2.4-dinitro-benzene-sulfonate 14 35 1-methyl-2-phenyl-3-dodecyl-benzimidazoIe-reine 10 38 l-methyl-2-pheny1-3-dodecyl-benzinlidazole-mercapto-benzothiazolate 10 20 l-methy1-2-pl1enyl-3-dodeeyl-benzimidazole-mercapto-benzimidazolate 48 1-methy1-2-phenyl-3-do deeyl-benz ole-pentachloro-phenolate 34 Untreated control Example 2.?Venturia inaequalis (Fusicladium dend-riticurn) on apples One-year-old potted apple seedlings (Grahams Jubilee) are sprayed with aqueous emulsions prepared as said before in Example 1. After drying off, inoculation is effected in a moisture chamber by sprinkling over with conidia of Venturz'a inaequalis. The inoculated plants remain in the moisture chamber at 20-23 C. and a relative humidity of 98-100% for 48 hours and are then placed in a greenhouse until evaluation on the 18th to 20th day after inoculation. The casualty rate is stated in the same manner as in thepreceding example.

TABLE 2.-VENTURIA. INAEQ UALIS/APPLES Casualty rate at preparation concentrations in Preparation percent l-methyl-2-phenyl-3-dodecyl-benzimidazolehexaeyanoierrate 11 13 Untreated control.

Example 3.Venturia inaequalis Example 4 .Er-ysiphe polyphaga on gucnmber (cucumber powdery mildew) Young cucumber plants (Beste von Allen) are sprayed with aqueous liquors of the preparation in the stated concentrations. After drying off, they are placed in a greenhouse at 23-25 C. and a relative humidity of about 70% and inoculated with conidia of the fungus by dusting evenly. In the case of a curative application of the preparations, the spraying with the preparation liquors is carried out only after the inoculated plants show the first symptoms of infestation, i.e., 5-6 days after inoculation, by spraying twice at an interval of 3 days. Similarly to the preceding examples, the casualty rate is given in percent of the casualty of the untreated control plants.

The leaves of untreated plants, at the moment of evaluation, i.e., 14-16 days after inoculation, are completely covered by the mycelium of the fungus and begin to die off.

TABLE 3.ERYSIPHE POLYPHAGA/CUCUMBERS Casualty rate at preparation concentrations in percent Preparation Protective (appL-l Curative (appl.-2

spray) sprays) l-methyl-Z-phenyl- B-dodeeyl-benzimidazole-hexacyanolerrate 5 18 70 38 43 56 Untreated controL 100 100 1-methyl-2-phenyl-3 -dodecyl-6-chloro-benzimidazolehexacyanoferrate,

1-me-thyl-2-pheny1-3-dodecyl-6-nitroebenzimidazolehexacyano ferrate.

The compounds to be used according to this invention can be applied as suspensions or emulsions or also as dusts admixed with other inert materials such as talc, chalk, bentonite, clay, kiesel-guhr, etc.

When preparing dispersible sprays, the active compounds are mixed with inert materials (such as said before) and then ground in the presence of suitable wetting and dispersing agents. Their combined application with other (even inorganic) fungicides and/or insecticides is possible.

Example 5 30 grams (0.12 mol) of kalium-hexacyanoferrate are dissolved in 250 ml. of Water. This solution is poured slowly into a solution of 135 grams of 1-methyl-2-phenyl- 3-dodecyl-benzimidazole-bromide dissolved in 500 ml. of water. After stirring rapidly the precipitate of l-methyl-Z- phenyl-3-d.odecyl-benzimidazole-hexacyanoferrate is collected by filtration with suction, and washed with water to remove unreacted material. After drying the yield of the reaction product amounts to 88%. The compound is a slightly colored powder which melts under decomposition. All the other compounds mentioned in the foregoing examples as well as in the description may be prepared by exactly the same procedure. Sometimes it is advisable to dissolve one compound in an aqueous alcoholic solution or an aqueous acetonic solution to secure a precipitation in powderous form. Usually it is advisable to use the salt which contains the cation X- of the formula in the beginning of the description in a slight excess.

If the compound precipitates as an oil sometimes the raw material may be washed free from unreacted organic material by using ether or benzene, whereafter usually the salt crystallizes or solidifies. It then may be milled to a particle size as described.

We claim: 1. A benzimidazolium salt of the following formula l a N \X oR2 X \69/ R,

wherein R stands for alkyl having up to 4 carbon atoms, R stands for a member selected from the group consisting of phenyl, lower alkoxy phenyl, ch lorophenyl and lower alkyl phenyl, R stands for alkyl having 8 to '18 carbon atoms, R stands for a member selected from the group consisting of hydrogen, lower alkyl, lower alkoxy, nitro,

chloro and bromo, and X denotes a member selected from the group consisting of hexacyanoferrate, Z-nitrobenzene sulfonate, 2,4-dinitrobenzene sulfonate, reineckate, mercaptobenzothiazo-late, mercaptobenzimidazolate, pentachlorophenolate and naphthalene-1,5-disulfonate.

2. The 1 methyl 2 phenyl 3 dodecyl benzimidazole-hexacyanoferrate.

3. The 1 methyl 2 phenyl 3 dodecyl benzimidazole-2-nitrobenzene-sulfonate.

4. The 1 methyl 2 phenyl 3 dodecyl benzimidazole-Z.4-dini'trobenzene-sulfonate.

5. The 1 methyl 2 phenyl 3 dodecyl 5 ethoxybenzimidazole-reineckate.

6. The 1 -rnethyl 2 p methoXy-phenyl-3-dodecy1- benzimidazole-hexacyanoferrate.

7. The 1 methyl 2 phenyl 3 dodecyl benzimidazole O-nitro benzene-sulfonate.

8. The 1 methyl 2 phenyl 3 dodecyl benzimidazole -2.4-dini-trobenzene-sulfonate.

9. The 1 methyl 2 phenyl 3 dodecyl-benzimidazole-reineckate.

10. The 1 methyl 2 phenyl 3 dodecyl-benzimidazole-mercaptobenzene-thiazolate.

11. The 1 methyl 2 phenyl 3 dodecyl benzimidazole-mercapto-benzimidazolate.

12. The 1 methyl 2 phenyl 3 dodecyl benzimidazolee-penta-chloro-phenolate.

References Cited by the Examiner UNITED STATES PATENTS 2,043,164 6/ 1936 Graenacher 260-3092 2,056,449 10/ 1936 Graenacher et al. 260-3092 2,065,418 12/1936 Andersag et al 260299 2,104,491 1/ 1938 McKinney 167-42 2,312,923 3/1943 Martin et al. 260-3092 2,739,149 3/1956 Van Lare et a1 260309.2 2,876,233 3/1959 Herrling et a1 260309.2 2,890,150 6/1959 Baldwin et a1. 167-33 2,933,502 4/1960 Klopping 260-299 3,097,132 7/1963 Wiegand et a1 260-299 OTHER REFERENCES Barnes, Chem. Abstracts, vol. 36, page 7248 (1942).

Carlson et al., Chem. Abstracts, vol. 31, page 365 (1937).

Elderfield, Heterocyclic Compounds, vol. 5, pages 285, 288 (1957).

Ried et al., Chem. Abstracts, vol. 53, col. 1373 (1959).

Wiegand, German Auslegeschrift, 1,040,752, Oct. 9, 1958, 3 pages.

NICHOLAS S. RIZZO, Primary Examiner.

IRVING MARCUS, D U V A L T. MCCUTCHEN,

WALTER A. MODANCE, Examiners. 

1. A BENZIMIDAZOLIUM SALT OF THE FOLLOWING FORMULA 